Analyte Identification in Transformed Electropherograms

Abstract

The present invention is directed to methods for identifying one or more analytes in a sample using electrophoresis. In one embodiment, the method comprises performing an electrophoretic separation by applying a potential across the separation path and thus generating a current and power therein and producing an electropherogram, integrating the current or the power to determine the cumulative current or power as a function of the separation time, transforming the electropherogram to a second electropherogram representing the signal as a function of the cumulative current or power, and identifying in the second electropherogram peaks that are correlated with the analytes in the sample. The invention also provides systems for performing the analysis and identification methods, as well as computer-readable products for performing the steps associated with the above methods.

Description

FIELD OF THE INVENTION [0001] This invention relates to a method and a system for detecting and / or measuring one or more analytes in a sample by electrophoretic separation, and more particularly, to methods for analyzing data generated by an electrophoretic separation. BACKGROUND OF THE INVENTION [0002] Separation by electrophoresis is a widely used analytical and preparative technique, especially in the life sciences. Electrophoretic separation is based on the movement of charged analytes in solution under the influence of an electric field. The rate of migration of an analyte depends on the size and shape of the analyte, the charge carried, the applied voltage and the resistance of the separation medium, Rickwood and Hames, Gel Electrophoresis of Nucleic Acids: A Practical Approach (IRL Press, Oxford, 1982). Many variations of the technique have been developed depending on the class of analyte being examined, e.g. DNA, proteins, small molecule drugs, and the like. In particular, c...

AI Technical Summary

Benefits of technology

[0017] The present invention provides a method, system and product for identifying, detecting or measuring one or more analytes that has several advantages over current techniques including, but not limited to, (1) accurate detection and quantification of peaks in electropherogram data, and (2) consistent electrophoretic analyses to overcome run-to-run, channel-to-channel and instrument-to-instrument variation, by correcting for fluctuations in the separation conditions that would otherwise cause fluctuations in the observed migration times or distances of analytes. The invention may also be employed to up-grade existing instruments for electrophoresis to give them the favorable properties of a constant power separation instrument without the need for expensive hardward alterations.

Problems solved by technology

A problem often encountered with electrophoresis is that the same sample constituents may appear on an electropherogram at different migration times for different samples of the same kind.

This creates a difficulty in many analytical procedures since analytes are typically identified either (i) by the appearance of a peak of a particular size or position on an electropherogram relative to the peaks of other sample constituents or relative to the peak(s) of a standard or (ii) by a characteristic migration time under predetermined separation conditions.

In either case, local variations in analyte migration rates reduce the accuracy of such identification.

These difficulties can be particularly troublesome in the separation of complex samples, where large numbers of analytes are sought to be identified in a single separation path, such as fragment ladders in DNA sequencing, and multiplexed analytical techniques, e.g. Singh et al, International patent publications WO 00 / 66607; WO 01 / 83502; WO 02 / 95356; WO 03 / 06947; and U.S. Pat. Nos. 6,322,980 and 6,514,700.

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